The load beds of vehicles are used to transport a large variety of goods around the road network. Some of those goods comprise elongate articles such as pile cages for reinforcing concrete piles, tree trunks, underground pipes and the like. It is a feature of these elongate articles that they must be lifted onto and off from the load bed by crane, i.e. it is not normally possible to use a fork lift truck to lift such articles as is the case with palletised articles for example. The load bed is usually fitted with a retaining structure, typically comprising a set of removable or permanent retaining posts at selected intervals along each of the longitudinal sides of the load bed in order to prevent the elongate articles from rolling or sliding off the side of the load bed, and the crane must lift the articles over the top of the retaining posts.
Because of the requirement to use a crane, it is necessary that an operator stand upon or close to the load bed so as to disconnect the lifting cables when an article has been lifted onto the load bed, and subsequently to connect the lifting cables when that article is to be lifted off the load bed.
In order to disconnect or connect lifting cables to the uppermost elongate articles, the operator may stand upon the stack of articles, and if so he or she will usually be standing over two meters above the ground. It will be understood that the loading and unloading of elongate articles in this way represents a significant health and safety hazard to the operator.
The operator could of course climb down from the load bed whilst each elongate article is loaded or unloaded, but climbing on to and off from a load bed is itself a difficult procedure not without danger, and so typically the operator will seek to is balance upon the stack of articles upon the load bed whilst other articles are loaded or unloaded.